Fluid tight joint



Sept. 5, 195% H. N. PRICE 2,521,127

FLUID TIGHT JOINT Filed flay 8, 1948 INVENTOR. HARRY N. PRICE.

ATTURNEY ist ned Sept. 5,1950

rum) TIGHT om'r Harry N. PricaEast Paterson, N. J., assignor to Wright Aeronautical Corporation, a corporation of New York I Application May 8,1948, serial No. 25,978

This invention relates to iiuid tight tube or pipe joints and is particularly directed to'a iluid i ht Joint which does not require predetermined adjustment of a tightening member, such as a noiifitin order to insure proper assembly of the Theinvention has been designed for use in connection with oil and fuel pressure lines of aircraft engines. As will appear, however, the invention is of general application. Aircraft engines require a large number of oil and fuel lines and for reasons of assembly and fabrication a larger number of fluid tight joints are required. in said lines. Such Joints are frequently disposed in relatively inaccessible; locations on the engine. Accordingly an object of this invention comprises the provi- ,sion of a fluid tight joint which is relatively simpie to assemble and in which no portion of the Joint needs to be tightened or adjusted to make the joint fluid tight. A further object of. the invention comprises thepltovision of a fluid tight wh m. (01. 285-90) a 2 control of the external diameter of said tube than is available in commercial tubing. A collar I8 is secured to and about the swaged end 16 of the tube lfor example by brazing or welding. It is essential that the junction between the collar I8 and the tube end it be fluid tight.

' Anannular external groove 20 is machined in 1 the collar )8, the external diameter'oi the bottom of said groove being accurately controlled. The resulting channel shaped cross-section of the collar l8 provides for maximum rigidity of said collar with a minimum of material. The external diameter of the channel sides of the collar ii are slightly less than the internal diameter 01' the joint in which the joined members are secured in fluid tight relation and against separation merely by snapping a split ring into position.

A stilliurther object of this invention comprises the provlsionof a fluid tight Joint in which the joined members are not rigidly connected together mechanically. In accordance with the present invention the Joint has limited axial and angular freedom whereby small variations in the length and. angularity oi thejoined members do not w. "swon said members. In adc'li um oi space and is light in weight, both of these features quite important i'onany device intended for-aircraft use.

Other objects of theinvention will bear -nt upon rea the annexed 11 2; dein connection with the drawing in a 1 teen sectional view of a joint inc 1: I 0g e13 is sectionaiview Q is an i view 'n to Figure 1 but oi a modification oi the inventionr o fe r ively thin wall tube It for conveying a fluid under t e to or from abody member i2 ds into a cylindrical chamber or here l4 wi said body member. The inner end of the tube 6 I; HIE sllihfly, as ted at it, to-provide a more'accurate bore or chamber it thereby permitting slight misalinement or angularlty of the tube iii and body member li. An annular packing ring 22 of re silient rubber-like material is disposed within the groove ill, between the bottom of said groove and the adjacent internal wall of the chamber or. bore It, 1 I As illustrated in the exploded view of Figure 3, the packing ring 22, in its free condition, has a circular cross-section and has a free internal diameterwhich is slightly smaller than the diameter oi the bottom of the? groove all and has a free external diameter which is slightly larger than the'internal diameter of the chamber or bore it. As used in the specification and claims, by free condition and free diameter" of the packing ring 22 is meant the condition and diameter,

i respectively, of said ring when no external forces, tion, the Joint of the invention requiresonlya when it is disposed between the bottom of the groove 20 and the internal wall of the chamber it thereby preventing leakage of fluid between the body member I! and the collar .18 past the ring 22. It should also be noted that the axial length of the groove 20 is larger than the axial length of the packing ring 22 whensaid ring is compressed between the bottom of said groove and the internal wall of a chamber it. This axial clearance at the ends of the resilient packin ring 22 improves its sealing properties over. those obtainable with no such axial clearance. This improvement probably results from the fact that with said axial clearance, the high pressure within the Joint acts against the entire left end (Figure 1) of the packing ring 22 to tightly squeeze said ring against the right end of the groove 20 as well as against the wall of the chainthan the outside asaaiar 3 pressure. If the reverse is the case, the sealing operation is unchanged except thepackingringfl isnowsqueeledbythefluid pressure. against the left end (Figure 1) of its groove 1.,

A shoulder 24 is formed at the inner end of the chamber ll, said shoulder being engageable by the collar II to limit axial travel of the tube it into the body member i2. Axial separation of the tube II from the body member I! is prevented by a split ring 26 which is designed to snap radially outwardly into a groove II adJacent the outer end of the chamber ll. If the internal dimeter of the split ring 2. is small enough it will be engageable by the collar II to prevent axial movement oi said collar and the tube ll out from the chamber i4. I

The split ring ll preferably is of the type ill trated in Figure 2 in which the split ends of the ring are provided with inturned cars it having holes I: to facilitate insertion and removal of said ring. In addition the radial width of the ring varies, as'illustrated, so that, throughout its range of diametrical contraction or expansion, its external periphery always approximates a circle. Buch split rings are commercially available only in a limitednumber of sizes. Therefore, in a given installation, it may be diflicult to provide suiiicient radial overlap between the internal di-- ameter of the split ring I. and the external diameter of the outer end of the collar II. In such a situation, an annular metallic washer 84 is interposed between the split ring it and the collar, as

said collar can assume any axial position between said shoulder and washer. This construction permits substantial variation in the length of the tube ll without aifectingthe tightness of the Joint between said tube and the body membe I! and without imposing any stress on said tube or body member. In addition, the small clearance between the channel sides of the collar II and the internalwall of the chamber ll permits slight angularity between the tube II and the body member it without subjecting said tube and member to bending stresses and withoutanecting is relatively light in weight and occupies only a small amount of space. To disengage the Joint between the tube ll andbodymember ilitisonly necessary to contract the split ring I suiiiciently so as to remove said ring from its groove ll whereby the tube II can be pulled out from its associated body member II.

In order that the resilient packing ring provides a fluid tight joint between the .tube II and the body member I: under high fluid pressures as under low iiuid pressures, it is essential that the inner and outer annular walls, engaged by said packing ring, be accurateiy'made so that their bottom of the groove II can readily be machined quite accurately.

The resilient packing ring can be disposed directly about the thin walled tube if the external diameter of said tube can be obtained within the necessary small manufacturing tolerance required by said packing ring for a good iiuid tight joint. Figure 4 illustrates such a construction.

In Figure 4, a thin walled tube ll extends into a body member (I having a chamber or bore 04 opening therein. A collar It is secured to and about the tube LI-for example by welding or brazing-at a substantial distance from the end of said tube. The collar II is disposed within the chamber 44 and is spaced. axially outwardly of an annular shoulder 40 formed at the bottom of said chamber. a resilient packing ring so of Q into the body member .4! beyond the shoulder ll toward another shoulder ll, said latter shoulder limiting travel of the tube 0 into the body memthe tightness of the Joint therebetween. Another feature or the Joint between the tube II and thebodymember liisthatthereisnorigidma chanioal connection between said tube and member. Actually the resilient rubber-like packing ring 22 is disposed between the tube II and the tionally isolate said tube and body member.

The resilient rubber-like packing ring I! is disposed within the groove II prior to assembly of the tube It and the bodymember II. In assembling the tube II and the body member" if, said tubewithits collar il andpackingringflisinserted into the chamber it in said body member. Then the split ring I. is snapped into position within the groove ll within the chamber I to complete the assembly. No other operation or adjustment is necessary to insure tightneor completeness of the Joint between the tube "and the body member l2. As a result of the provision of the split ring 20 for locking the elements of the Joint together, it is impossible for the installer to tighten the Joint too much or too little. In addition, because of the split ring It, the joint ber 42. The axial dimensions of the Joint are such that the end of the tube ll engages the shoulder II before the packing ring II is squeezed between the shoulder 48 and the collar 48. Accordingly, as in Figure 1, regardless of the axial position of the tube ll in the member I! the axial dimensions of the annular space within which the resilient packing ring II is disposed is always larger than the width of said ring when which snaps or expands radially outwardly into ring a is slipped over the end of the tube u ms tube is inserted into the chamber ll of the member 42 and then the split ring I is snapped into position to complete the assembly.

With this construction of Figure 4, it is not necessary that the collar ll be secured to the tube 40 in iiuid tight relation in order that the to slip off the end of its tube "when the joint is disassembled. In addition, in Figure 1 it is not essential that the external diameter of its tube Ill be made as accurately as the tube 40 of Figure 4 in order to insure a fluid tight junction under a large range of fluid pressures.

While I have described my invention in detail in its present preferred embodiments, it will be 1. A fluid tight joint comprising a flrsttubular member; a collar disposed about and secured to said first member; a second member having a chamber with an open end, said chamber having an annular groove formed in its wall and adjacent to its said open end with said groove facing radially inwardly into said chamber, said first member extending into said chamber with its said collar disposed within said chamber axially 'inwardly of said annular groove; a ring received within said annular groove and projecting radially inwardly therefrom into said chamber for retaining said collar and first member within .said chamber; and an annular packing ring of resilient rubber-like material disposed within said chamber in an annular space about said first member, said packing ring being radially compressed in said annular space and having a free external diameter greater than that ortion of the radially outer wall of said space engaged by said packing ring and having a free internal diameter smaller than that portion of the radially inner wall of said space engaged by said packing ring.

2. A fluid tight joint as recited in claim 1 in which said first mentioned ring is split to facilitate insertion and removal of said ring from said annular groove.

3. A fluid tight joint comprising a first tubular member having a collar disposed aboutand secured to said first member, said collar having an external annular groove disposed between its ends; a second member having a chamber with an open end, said chamber having an annular groove formed in its wall adjacent to its said open end with said groove facing radially inwardly into said chamber, said first member extending into said chamber with its said collar disposed within said chamber axially inwardly of said annular chamber groove; a split ring received within said annular chamber groove and projecting radially inwardly therefrom into said annular packing ring of resilient rubber-like material dls-. posed within the external groove in said collar, said packing ring being radially compressed between the bottom of said external groove and the adjacent wall of said chamber and having a free external diameter greater than that portion of the wall of said chamber engaged by said packing ring and having a free internal diameter smaller than the bottom of said external groove.

4. A fluid tight joint as recited in claim 3 in which said second member has a shoulder facing the .open end of its chamber and disposed axially Number chamber groove for retaining said collar and first as member within said chamber; and an annular inwardly of its annular groove for limiting travel of the first member into said chamber.

5. A fluid tight joint as recited in claim 4 in which said collar is. disposed axially between said split ring and shoulder and the axial length of said collar is small enough to permit limited axial movement of said collar and its first member between said split ring andshoulder.

6. A fluid tight joint comprising a first tubular member having a collar disposed about and secured to said first memberadjacent to but spaced from an end of said member; a second member having a chamber with an open end, said chamber having an annular groove formed in its wall adjacent to its said open end with said groove facing radially inwardly into said chamber, said chamber also having an annular shoulder facing the open end of said chamber and spaced axially inwardly of said annular chamber groove, said first member extending into said chamber with its said collar disposed within said chamber between said chamber shoulder and annular groove; 8. split ring received within said annular chamber groove and projecting radially inwardly therefrom into said chamber for cooperation with said collar to retain said collar and first member within said chamber; and an annular packing ring of resilient rubber-like material radially compressed in the annular space about said first member between said collar and said shoulder, said packing ring having a free external diameter greater than that portion of the wall of said chamber engaged by said packing ring and having a free internal diameter smaller than that portion of said first member engaged by said packing ring.

7. A fluid tight joint as recited in claim 6 in which means are provided to prevent travel of said first member into said chamber to an extent suflicient to squeeze said packing ring between said collar and shoulder.

HARRY N. PRICE.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Name Date Wolfram Dec. 17, 1946 FOREIGN PATENTS Country Date Australia Apr. 26, 1939 Australia June 10, 1942 Number 

